It is generally known in metal container manufacturing processes to provide features on metallic containers such as raised forms and indicia using opposing, offset inside and outside shaped tooling dies. Outer dies frequently comprise inward protrusions, and inner dies comprise outward protruding features. These devices are typically applied to open ended straight wall containers before necking the container. However, these processes generally do not allow for features to be formed in the neck and/or shoulder area, and existing tools and methods of manufacturing fail to provide for large radius shoulders with common necking technology.
Surface features are generally known to be provided on metal containers using opposing, offset inside and outside shape dies, outer dies with inward protrusions, or inner dies with outward protruding features. Such known devices are typically applied to open ended straight wall containers prior to necking the container. Such known processes do not contemplate or allow for features to be provided in a neck or shoulder region of a container, and require more complexity in tool designs which typically cannot be run at commercially required speeds.
Conventional drawn and ironed aluminum and steel containers are drawn into cups, redrawn into a smaller diameter cup and ironed for increased length and to provide closed cylindrical shapes on bottle shaped containers. After coating applications and curing, the opening size is reduced by various necking methods, die necking, or some combination of die necking and spin necking or spin flow necking to be prepared for application of a closure of various styles such as conventional beverage end closures. Ropp (roll on pilfer proof) closures, or bottle crown caps. In the process of creating the necks of such containers, a shoulder is created where the cylindrical wall of the can body meets the neck. Shoulder configurations are generally arcuate in shape with radii in the range from 0.10 inches to about 2.0 inches.
Conventional die necking reduces the diameter of the container by contact of the cut edge of the container with an axi-symmetric forming die which forces the metal inward to effect a slight reduction in the diameter of the opening. A plurality of necking operations are performed to produce the desired opening size depending on the starting diameter and opening size. An axi-symmetric pilot die is generally used with the necking on the inside of the container to control the metal flow and reduce wrinkling. The forming die radii have generally been in the range of 0.10 inches to 0.50 inches for lightweight metal beverage containers. Conventional drawn and ironed metal containers are then finished with a flange to be able to be closed with a container end closure. Metallic bottle shaped containers are typically finished with either a crown curl or a threaded finish which can receive an aluminum or steel closure.
Some shaping and embossing processes to modify the cylindrical shapes are known in the art such as blow molding inside a die, spin flowing forming, and progressive die necking deep into the body of the container followed by expansion operations to create generally axi-symmetric shapes. However, many of these processes are time consuming, expensive, and not conducive to forming unique outward or inwardly shaped geometries in the shoulder or neck region of the bottle shaped container.